Wu Xin, Yan Qiao, Hedayat Ahmadreza, Wang Xuemei
College of Engineering, Sichuan Normal University, Chengdu, 610101, Sichuan, China.
Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, 80401, USA.
Sci Rep. 2021 Nov 22;11(1):22685. doi: 10.1038/s41598-021-02234-x.
Elastic waves have different attenuation laws when propagating in various materials, which is one of the important challenges in the application of non-destructive testing methods, such as acoustic emission (AE) technology in geotechnical engineering. The study presented in this paper investigated the influence mechanism of concrete composition materials and parameters on the propagation law of elastic waves using concrete specimens produced in six different particle sizes of sand or gravel. The burst AE signal was generated through the lead-breaking experiment, and ceramic piezoelectric sensors were used to record the signal waveform at different propagation distances. Through parameter analysis, spectrum analysis, and pattern recognition techniques, the influence of the concrete aggregate particle size on AE wave propagation and attenuation was revealed. The results show that the attenuation of elastic wave amplitude, energy spectral density, and frequency all were positively correlated with the aggregate particle size, and the elastic wave spectrum center of gravity generally decreased with the propagation distance. The ring count gradually decreased with the propagation distance, and the specimens with a larger aggregate particle size underwent a relatively faster ring count attenuation rate. The rise time increased rapidly with the propagation of the elastic wave, and the specimens with a larger aggregate particle size experienced a relatively rapid increase in rise time. In addition, in the feature spaces of ring count-amplitude and rise time-amplitude, the size of aggregate has an obvious influence on the distribution of these feature vector.
弹性波在不同材料中传播时具有不同的衰减规律，这是非破坏性检测方法应用中的重要挑战之一，比如岩土工程中的声发射（AE）技术。本文的研究使用六种不同粒径的砂或砾石制作混凝土试件，研究了混凝土组成材料和参数对弹性波传播规律的影响机制。通过断铅试验产生突发声发射信号，并使用陶瓷压电传感器记录不同传播距离处的信号波形。通过参数分析、频谱分析和模式识别技术，揭示了混凝土骨料粒径对声发射波传播和衰减的影响。结果表明，弹性波振幅、能量谱密度和频率的衰减均与骨料粒径呈正相关，弹性波频谱重心一般随传播距离减小。振铃计数随传播距离逐渐减小，骨料粒径较大的试件振铃计数衰减率相对较快。上升时间随弹性波传播迅速增加，骨料粒径较大的试件上升时间增加相对较快。此外，在振铃计数-振幅和上升时间-振幅的特征空间中，骨料粒径对这些特征向量的分布有明显影响。
